title: Increase in the astaxanthin synthase gene (crtS) dose by in vivo DNA fragment assembly in Xanthophyllomyces dendrorhous.
abstract: BACKGROUND
  Xanthophyllomyces dendrorhous is a basidiomycetous yeast that is relevant to biotechnology, as it can synthesize the carotenoid astaxanthin. However, the astaxanthin levels produced by wild-type strains are low. Although different approaches for promoting increased astaxanthin production have been attempted, no commercially competitive results have been obtained thus far. A promising alternative to facilitate the production of carotenoids in this yeast involves the use of genetic modification. However, a major limitation is the few available molecular tools to manipulate X. dendrorhous.
  
  
  RESULTS
  In this work, the DNA assembler methodology that was previously described in Saccharomyces cerevisiae was successfully applied to assemble DNA fragments in vivo and integrate these fragments into the genome of X. dendrorhous by homologous recombination in only one transformation event. Using this method, the gene encoding astaxanthin synthase (crtS) was overexpressed in X. dendrorhous and a higher level of astaxanthin was produced.
  
  
  CONCLUSIONS
  This methodology could be used to easily and rapidly overexpress individual genes or combinations of genes simultaneously in X. dendrorhous, eliminating numerous steps involved in conventional cloning methods.
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla, Santiago 653, Chile. jalcainog@u.uchile.cl.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Contreras
authors.forename: Salvador
authors.initials: S
authors.lastname: Barahona
authors.forename: María Cecilia
authors.initials: MC
authors.lastname: Rojas
authors.forename: Marcelo
authors.initials: M
authors.lastname: Baeza
authors.forename: Víctor
authors.initials: V
authors.lastname: Cifuentes
authors.forename: Jennifer
authors.initials: J
authors.lastname: Alcaíno
mesh_terms: D001487:Basidiomycota / Q000201:enzymology / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018628:Gene Dosage; D015966:Gene Expression Regulation, Fungal; D005818:Genetic Engineering / Q000379:methods; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D024341:Xanthophylls; C005948:astaxanthine; D008025:Ligases